文献类型：期刊文献

英文题名：Variation in soil water uptake and its effect on plant water status in Juglans regia L. during dry and wet seasons

作者：Sun, Shou-Jia[1] Meng, Ping[2] Zhang, Jin-Song[2] Wan, Xianchong[1]

通信作者：Wan, XC[1]

机构：[1]Chinese Acad Forestry, Inst New Forest Technol, Beijing 100091, Peoples R China;[2]Chinese Acad Forestry, Res Inst Forestry, State Forestry Adm, Key Lab Tree Breeding & Cultivat, Beijing 100091, Peoples R China

年份：2011

卷号：31

期号：12

起止页码：1378-1389

外文期刊名：TREE PHYSIOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000298247500009)】；

基金：This study has been supported by the basic research foundation from the institute of new forest technology, Chinese Academy of Forestry (CAFINT2010K09) and the 12th 5-year key technology program of China (2011BAD38B02).

语种：英文

外文关键词：branch PLC; gas exchange; Juglans regia; root distribution; stable hydrogen isotopes; water source

摘要：Temporal and spatial variations in the water status of walnut trees (Juglans regia L.) and the soil in which they were growing were traced by analyzing the differences in hydrogen isotopes during spring and summer in a 7-year-old walnut stand. Walnut root dynamics were measured in both dry and wet seasons. Walnut roots were mainly distributed in the upper soil (0-30 cm depth), with around 60% of the total root mass in upper soil layers and 40% in deep soil layers (30-80 cm depth). The upper soil layers contributed 68% of the total tree water requirement in the wet season, but only 47% in the dry season. In the wet season, total roots, living roots and new roots were all significantly more abundant than in the dry season. There were significant differences in pre-dawn branch percentage loss of hydraulic conductance (PLC), pre-dawn leaf water potential and transpiration between the dry and wet seasons. Water content in the upper soil layers remarkably influenced xylem water stable-hydrogen isotope (delta D) values. Furthermore, there were linear relationships between the xylem water delta D value and pre-dawn branch PLC, pre-dawn leaf water potential, transpiration rate and photosynthetic rate. In summary, J. regia was compelled to take a larger amount of water from the deep soil layers in the dry season, but this shift could not prevent water stress in the plant. The xylem water delta D values could be used as an indicator to investigate the water stress of plants, besides probing profiles of soil water use.